Generally, when a vehicle having a manual transmission is driven in an ordinary manner, the brake pedal and clutch pedal must be depressed to stop the vehicle. When the driver wants to restart the vehicle after stopping, he or she must release the brake pedal and press the accelerator pedal and at the same time slowly release the clutch pedal.
When the vehicle is restarted on an up-slope after stopping, the driver selects a low-gear and releases the brake pedal, at the same time presses the accelerator and releases the clutch pedal to start the vehicle. Here, if the clutch pedal is released too quickly, the engine will stall. On the other hand, if the clutch is released too slowly, the vehicle will slip backward which may cause it to crash into a vehicle or other object behind it. Therefore, great technical skill is required to restart a vehicle stopped on a slope.
Moreover, a driver may operate a conventional braking system to park the vehicle on a slope, but if the braking force is not sufficient to maintain the vehicle in the parked position, the vehicle will roll downward. Therefore, unexpected accidents occur often.
Also, when a vehicle is driven backward, i.e., a vehicle is going in reverse, the driver cannot completely survey the area behind the vehicle using the rear view mirror and may be unaware that there is an obstacle (like a child) behind the vehicle. This may frequently result in many accidents.
An Automatic Brake Control System" for controlling a vehicle on a slope is shown in U.S. Pat. No. 4,590,406.
The system in accordance with the patent closes the brake fluid passage between the master cylinder and the brake cylinder, and this prevents the reverse flow of fluid in the brake fluid passage. Therefore, the brake force is maintained during any parking conditions after a vehicle must be stopped by the driver.
As a system disclosed in this patent is merely a locking mechanism, the operation of this system has many disadvantages. For instance, this system maintains the braking force when the clutch is engaged.
As the oil passage is either ON or OfF by the use of two valves, one of which has an aperture which has a diameter smaller than that of the oil passage, a time-delay is required for releasing the braking force.
On the other hand, when repeated instantaneous braking operations are required for the vehicle, repeated operation of the brake and clutch pedal is necessary. In such a situation, the driving cannot be smooth.
In addition, the parts of this prior art system require high precision and high production costs.
Another prior art disclosure involves an apparatus which uses pressurized air and a protect system. This apparatus is designed to operate the braking mechanism or absorb the shock when the vehicle crashes; however, this apparatus cannot prevent accidents in advance. This prior art apparatus decreases the damage after a collision.